Okay, by now we know how to make a profit with a system, but is it also possible to prevent to loose money with MQL4? Well, we will see. With our very basic Expert Advisor we have traded the Australian Dollar against the U.S. Dollar. I will remove the visible mode to speed things up a little bit. And these are our results. We had a high peek above 1070 Dollars, but our end result was only 1019 dollars. So how could we prevent to loose 50 dollars? Actually this only takes two more lines of code. So hit F4 to go back to your Expert Advisor in Metaeditor and add these two lines here. If your account balance goes above 1070 dollars we want to remove the automated trading expert. Let’s compile that, return to the Metatrader and run that test again. And now we made 1070 dollars as an end result.